Cassini’s First Grand Finale Images Are Stunning—But What Are We Really Looking At?

Image: NASA/JPL-Caltech/Space Science Institute

It was 11:56 pm Wednesday night when a Deep Space Network receiver picked adult a vigilance from NASA’s Cassini orbiter as it emerged from a initial outing by a opening between Saturn and a gas giant’s rings. In a indirect information came cinema of a planet’s north stick and cloud tops from usually 1,800 miles (3000 kilometers) away—our closest demeanour nonetheless during a top partial of Saturn’s atmosphere, where a vigour is about a same as it is during sea turn on Earth.


Researchers during a Jet Propulsion Laboratory were awestruck by a detail, though we was left with a question: What would it be like to indeed revisit a top reaches of Saturn’s skies?

What primarily held my courtesy in a new images were a splendid spots dotting a skinny bands opposite a planet’s face. My arrogance was that these were intensity flickers of lightning prisoner by Cassini’s Imaging Science Subsystem Wide Angle Camera, though no. “We didn’t locate any lightning [on Wednesday night],” Caltech highbrow Andy Ingersoll, an consultant in heavenly atmospheres, told me when we called him to plead a Saturnian continue I’d need to container for.

Unprocessed picture of Saturn’s atmosphere, taken on Apr 26th. Image: NASA/JPL-Caltech/Space Science Institute

According to Ingersoll, a lighter blobs graphic above are clouds of ammonia floating about 93 miles (150 kilometers) atop a subsequent closest covering of a atmosphere. If we were dangling in a hydrogen balloon (not helium, as a helium balloon in a hydrogen atmosphere would “sink like a rock,” Ingersoll said), these ammonia clouds would demeanour really identical to a H2O fog cumulus clouds here on Earth.


“There substantially are clouds of H2O fog down deeper though we can’t see them as good since it’s frozen. The H2O [freezes] during larger abyss than a ammonia,” pronounced Ingersoll. “So, we typically see ammonia clouds and that’s what we consider these are, as comfortable atmosphere rises adult and condenses out cloud particles.” Warm, it should be noted, is a relations term—temperatures normal -270 Celsius in Saturn’s top atmosphere, so move a coat.

On Wednesday night, Cassini prisoner a array of photos that began with a spinning gyre in a core of Saturn’s north stick hexagon. Traveling southward, it eventually flew by a equator during a sprightly 77,000 miles per hour (124,000 kph). If a camera was sharpened in color, we would have seen a sapphire blue of a north pole’s middle vortex, though a spacecraft’s speed compulsory monochrome photography.

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